1. Technical Field
Embodiments of the invention generally relate to electronics, and, in particular, to memory devices.
2. Description of the Related Technology
Certain errors can repeatedly occur when writing data to memory. For instance, memories can encounter “hard errors” in memory cells. A hard error can refer to a repeatable error that consistently returns incorrect data. Some hard errors can result from a memory cell getting stuck in a particular state. As one example, a binary memory cell with a hard error can return a logical 0 value regardless of whether a logical 0 or a logical 1 is written to the memory cell. In this example, the memory cell with the hard error encounters the same failure when reading data from the memory cell. More specifically, a memory cell stuck in a logical 0 state will encounter failures of reading a logical 0 when trying to read a logical 1 written to the memory cell.
Hard errors can occur in various types of memories, such as phase-change memory (PCM), also known as PCRAM or PRAM. PCM is a form of non-volatile memory made from a phase-change material. An example of a phase-change material is Germanium-Antimony-Tellurium (GST). When a cell of GST material is heated beyond its melting point and cools relatively rapidly, the phase-change material of the cell is in an amorphous state and can have a resistance associated with a first state, such as logic 0. When the cell of GST material is heated and is cooled relatively slowly, the phase-change material of the cell is in a crystalline state and can have a resistance associated with a second state, such as logic 1. The cell of GST material can also be heated to a relatively lower temperature, such as a temperature associated with crystallization to achieve the crystalline state. Intermediate states are also possible for multi-level cells.
Accordingly, a need exists for correcting for hard errors in memories, such as PCMs.
To avoid repetition of description, components having the same or similar function may be referenced by the same reference number.